ISO/FDIS 22834

Large yachts -- Quality assessment of life onboard -- Stabilization/sea keeping

Titre manque

General Information

• Status: Published
• ICS: 47.040 - Seagoing vessels
• Technical Committee: ISO/TC 8/SC 12 - Ships and marine technology - Large yachts
• Drafting Committee: ISO/TC 8/SC 12/WG 5 - Quality assessment and acceptance criteria
• Current Stage: 5020 - FDIS ballot initiated: 2 months. Proof sent to secretariat
• Start Date: 14-Dec-2021
• Completion Date: 14-Dec-2021

Standards Content (sample)

FINAL
INTERNATIONAL ISO/FDIS
DRAFT
STANDARD 22834
ISO/TC 8/SC 12
Large yachts — Quality assessment
Secretariat: UNI
of life onboard — Stabilization/sea
Voting begins on:
2021-12-14 keeping
Voting terminates on:
2022-02-08
RECIPIENTS OF THIS DRAFT ARE INVITED TO
SUBMIT, WITH THEIR COMMENTS, NOTIFICATION
OF ANY RELEVANT PATENT RIGHTS OF WHICH
THEY ARE AWARE AND TO PROVIDE SUPPOR TING
DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
Reference number
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO-
ISO/FDIS 22834:2021(E)
LOGICAL, COMMERCIAL AND USER PURPOSES,
DRAFT INTERNATIONAL STANDARDS MAY ON
OCCASION HAVE TO BE CONSIDERED IN THE
LIGHT OF THEIR POTENTIAL TO BECOME STAN-
DARDS TO WHICH REFERENCE MAY BE MADE IN
NATIONAL REGULATIONS. © ISO 2021
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ISO/FDIS 22834:2021(E)
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© ISO 2021

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© ISO 2021 – All rights reserved
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ISO/FDIS 22834:2021(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction .................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ..................................................................................................................................................................................... 1

3 Terms and definitions .................................................................................................................................................................................... 1

4 Waves ............................................................................................................................................................................................................................... 2

4.1 Irregular waves ...................................................................... ................................................................................................................ 2

4.2 Equivalent scatter diagram, wave height and wave periods ......................................................................... 3

5 Heading .......................................................................................................................................................................................................................... 3

6 Speeds .............................................................................................................................................................................................................................. 3

7 Definitions of the areas on board ......................................................................................................................................................3

8 Calculation of MSI and EGA .......................................................................................................................................................................3

8.1 General ........................................................................................................................................................................................................... 3

8.2 Weighting factor .................................................................................................................................................................................... 4

9 Stabilization systems ...................................................................................................................................................................................... 5

10 Calculation of the ship motions (EGA and MSI) ................................................................................................................... 5

Annex A (informative) Definitions and descriptions ......................................................................................................................... 6

Annex B (informative) Guided example ........................................................................................................................................................12

Bibliography .............................................................................................................................................................................................................................16

iii
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ISO/FDIS 22834:2021(E)
Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards

bodies (ISO member bodies). The work of preparing International Standards is normally carried out

through ISO technical committees. Each member body interested in a subject for which a technical

committee has been established has the right to be represented on that committee. International

organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.

ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of

electrotechnical standardization.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the

different types of ISO documents should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www.iso.org/patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to

the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see

www.iso.org/iso/foreword.html.

This document was prepared by Technical Committee ISO/TC 8, Ships and marine technology,

Subcommittee SC 12, Large yachts.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www.iso.org/members.html.
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ISO/FDIS 22834:2021(E)
Introduction

The lack of standards and criteria for the assessment of the ship-motion related to the risk of discomfort

onboard of large yachts was reported to be an important issue for the industry, brokers, owners and

representatives. There was not a recognized and accepted procedure, criteria and rating that can

be used to compare yachts among each other and evaluate the impact of stabilization systems in the

improvement of the comfort onboard.

The increased demand for comfort onboard of large yachts led to the development of several types

of stabilization systems and to design large yachts with ship motions in mind. The intention of this

document is to define an objective scale for comparison of different levels of comfort at several areas

onboard of a large yacht in transit and at zero speed (DP or at anchor).
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FINAL DRAFT INTERNATIONAL STANDARD ISO/FDIS 22834:2021(E)
Large yachts — Quality assessment of life onboard —
Stabilization/sea keeping
1 Scope

This document provides a comparative scale (no judgement) of motion-related comfort onboard yachts

to be used for technical and commercial benefit. The scale consists of a maximum number of 5 stars,

the higher the amount of stars, the higher the comfort onboard. It allows the selection of the most

suitable yacht for a specific purpose, evaluates the impact of stabilization systems, compares designs

and identifies the most comfortable position onboard.

The methodology, work flow and criteria proposed in this document are subject to possible

improvements and do not take into account certain important aspects that influence the comfort

onboard.

The following aspects are not covered in this document: jerk, the method to derive roll damping, stern

quartering seas, risk of parametric roll, the influence of the steering devices, green water and waves

impacts, compensation for yacht size, gender and age dependency, habituation.

By explicitly listing the aspects that are not covered in this document, the reader becomes aware of

them and can improve the assessment with dedicated considerations.
2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements of this document. For dated references, only the edition cited applies. For

undated references, the latest edition of the referenced document (including any amendments) applies.

ISO 2631-1:1997, Mechanical vibration and shock — Evaluation of human exposure to whole-body vibration

— Part 1: General requirements
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.

ISO and IEC maintain terminology databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
comfort

subjective state of well-being or absence of mechanical disturbance in relation to the

induced environment (mechanical vibration or repetitive shock)

Note 1 to entry: Many of the factors contributing to a comfortable state for crew and passengers are indicated in

Figure 1.

Note 2 to entry: Some of these factors are being assessed and described in existing ISO standards, such as

ISO 2631-1 for the vibrations and several others for the noise with respect to human beings.

Note 3 to entry: The comfort factors addressed in the study presented in this document are the ones related to

motion, postural stability and the motion sea sickness.
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ISO/FDIS 22834:2021(E)

Note 4 to entry: Some of the factors influencing comfort are a function of the extension to the exposure to that

specific factor and its intensity, as well as to the gender, age and previous experiences of the subject experiencing

discomfort. The mental state of the subjects plays also a very important role.
Figure 1 — List of elements contributing to comfort onboard
3.2
effective gravity angle
EGA

angle between the transversal acceleration and the sum of the vertical acceleration and the standard

gravitational acceleration containing the static roll angle and also the dynamic components

Note 1 to entry: The EGA is the direct measure of the need to look for support for standing persons, but also for

tipping or sliding of objects.
3.3
incidence of motion sickness
MSI

simple and concise statistically-based measure for predicting the incidence of motion sickness by

exposure to vertical accelerations

Note 1 to entry: MSI expresses the percentage of people on board that suffer from sea sickness after a certain

exposure time. For passengers vessels, a percentage of 10 % seems to be reported in literature.

Note 2 to entry: The duration of exposure is of one hour.
4 Waves
4.1 Irregular waves
Long crested irregular waves with a Jonswap wave spectrum shall be applied.
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ISO/FDIS 22834:2021(E)
4.2 Equivalent scatter diagram, wave height and wave periods

The combined equivalent scatter diagrams of the western Mediterranean (area 47 of the global waves

statistics GWS) and Caribbean seas (area 26 GWS) with a significant height between 1 m and 2 m and

the periods indicated in Table A.3 and Figure A.3 shall be used.
5 Heading

A right-handed coordinate system shall be used. The 135° heading (bow quartering) shall be used.

Table A.2 and Figure A.4 indicate the heading convention and reference system.
6 Speeds
The two following speeds shall be used separately:
— 0 knots;
— 12 knots.
7 Definitions of the areas on board

Independently on where they are located onboard, the following five areas shall be used as a minimum:

1. owners cabin (OC)
2. dining area (DA)
3. wheel house (WH)
4. crew area (CA)
5. beach club (BC)

The coordinates of the selected areas shall be obtained by considering the geometrical centre of these

areas with respect to the origin. The origin shall be reported. The Z-coordinate (vertical plane) shall be

determined by considering the deck height of the corresponding area, adding 1,2 m to this height.

When the areas are distributed in a non-symmetrical way, the assessment shall be done for the area

itself but also for the mirrored area with respect to the longitudinal ship’s plane as well. In this way, the

assessment is done for both the windward and leeward side of the non-symmetrical area.

When the destination of the areas onboard is not defined yet, at least five areas without name but

uniquely identified (area 1, area 2, etc.) shall be used for the assessment of the comfort onboard

following the procedure indicated in this document.
8 Calculation of MSI and EGA
8.1 General

For each of the five areas, the MSI and EGA shall be calculated and assessed in accordance with

ISO 2631-1:1997, Annex D.
The EGA shall be calculated using Formula (1):
 at() 
EGAt()=arctan (1)
 
at +g
 
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ISO/FDIS 22834:2021(E)
where
a transversal acceleration in [m/s ];
a vertical acceleration in [m/s ];
g standard gravitational acceleration in [m/s ].

NOTE The EGA contains not only the static roll angle but also the dynamic components [see Figure 2 and

Formula (1)]. The EGA is a direct measure of the need to look for support for standing persons, but also for tipping

or sliding of objects. Tipping occurs when the EGA is pointing outside the base of the subject. Sliding is dependent

on the friction between the subject and the surface on which it is standing.
Figure 2 — Determination of the EGA

The assessment of these two quantities (MSI and EGA) is done by verifying the simultaneous fulfilment

of the following criteria:
— The root mean square (RMS) of the EGA shall be lower than 2°;
— The MSI shall be lower than 10 %.

As indicated in Table B.2, there is a relation between the results of the calculations of MSI and EGA at

the indicated conditions (the ship’s speed, heading, wave height, periods, etc.) and the amount of stars.

The fulfilment of the criteria is given as percentage of time: the up-time. This term is also known as

workability.
8.2 Weighting factor

The equivalent weighting factors given in Table A.3 shall be used for each of the five areas onboard.

When there is the need to calculate the comfort on more than five areas onboard, equivalent weighting

factors shall be used.
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ISO/FDIS 22834:2021(E)
9 Stabilization systems

The calculation process shall be performed both with an active stabilization system and without a

stabilization system, but not with a passive stabilization system. When a yacht is equipped with passive

stabilization systems with elements that remain outside the hull, such a stabilization system contributes

to the generation of damping like a bilge keel. The system is excluded when considering the “without”

stabilization case. One of the purposes of the entire calculation process is to indicate the improvement

in comfort obtainable by adopting a stabilization system with respect to the yacht without any system.

The result is the number of stars per area onboard of the yacht without stabilization, and the number of

stars per area onboard obtainable with an active stabilization system. The difference in the number of

stars is owing to the contribu
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